(1) Field of the Invention
The present invention pertains to a head uspension for supporting a read/write head adjacent a rotary data storage device, and in particular to a head suspension having an actuator arm and load beam connected in a laminate, monocoque construction that minimizes mass and rotational inertia of the head suspension while maintaining or improving the head suspension stiffness, shock, resonance and deflection performance.
(2) Description of the Related Art
Most personal computer systems today employ direct access storage devices (DASD) or rigid disk drives for data storage. A conventional disk drive 210, such as shown in FIG. 15, contains a disk spindle that is rotated by an electric motor at several thousand revolutions per minute (RPM) while the disk drive is turned on. A plurality of magnetically coated recording disks 206 are mounted on the spindle for rotation therewith at axially spaced positions along the spindle. The number of disks and the composition of their magnetic material coating determines, in part, the data storage capacity of the disk drive.
Positioned adjacent the peripheries of the rotating disk 206 is a head actuator column 212. The head actuator column has a plurality of actuator arms 214 thereon, and each actuator arm supports one or more head suspensions 230 that extend in cantilever fashion from the actuator arm to distal ends of the head suspensions. In dynamic storage devices optical or magnetic read/write heads are supported on sliders, referered to collectively as 208, at the distal ends of each of the head suspensions 230. The plurality of actuator arms and their associated head suspensions support the read/write heads adjacent the top and bottom surfaces of each of the plurality of disks supported by the spindle.
Typically, the load beam of each head suspension is welded or secured in an equivalent manner to a base plate, and the base plate in turn is secured to the head actuator column.
In the pursuit of improving head suspension designs, the prime objective is to optimally balance low mass with a high enough rigidity or stiffness for any given head suspension design. Competing with the need for rigidity in the head suspension is the need to give the head suspension as low a mass as possible to minimize rotational inertia of the head suspension created by its rapid positioning movements and to reduce sensitivity to shock. This is especially true in the reduced size rigid disk drives employed in notebook and laptop computers where the disks are smaller and their data storage density is increased.
FIG. 1 shows one prior art design of a head suspension which achieves a reduction in the overall mass of the head suspension while maintaining desirable levels of rigidity and stiffness. In this prior art design, a load beam 2 is assembled directly to an actuator arm 3. The mass of the head suspension is reduced by eliminating the base plate and its mass.
The actuator arm is provided with mass reduction holes 6 and the forward or distal most mass reduction hole 6 in the distal region 5 of the actuator arm may also be employed as a tooling aperture that aligns with a tooling aperture 7 provided in the proximal region of the load beam 2 when assembling the load beam to the actuator arm. The proximal region 4 of the load beam, when assembled to the actuator arm distal region 5, runs along a lateral side of the actuator arm 3 adjacent but spaced from the weight reduction apertures 6 of the actuator arm. The projecting proximal portion of the load beam 4 is secured to the distal region 5 of the actuator arm by spot welds, adhesives or other equivalent methods.
In an effort to further improve the balance between reduced mass and increased rigidity or stiffness of a head suspension, the design concept of the present invention was arrived at where the head suspension is constructed as a laminate of a load beam and actuator arm that contains hollow cavities within the laminate construction giving the suspension a monocoque construction with enhanced stiffness and reduced mass.